Rheostat.



H. A. WALLACE.

RHEOSTAT.

APPLICATION FILED Nov, 21, 1916.

1 20,573 I Patented- Mar. 27, 1917.

FIG-.2

UNITED STATES PATENT OFFICE.

HERBERT A. WALLACE, OF PITTSBURGH, PENNSYLVANIA, ASSIGNOR TO THE UNION SWITCH & SIGNAL COMPANY, OF SWISSVALE, PENNSYLVANIA, A CORPORATION OF PENNSYLVANIA.

RHEOSTAT.

Specification of Letters Patent.

Patented Mar. 27, 1917.

Application filed November 27, 1918i Serial No. 133,558.

To all whom it may concern:

Be it known that I, HERBERT A. WALLACE, a citizen of the United States, residing at Pittsburgh, in the county of Allegheny and State of Pennsylvania, have invented certain new and useful Improvements in Rheostats, of which the following is a specification.

This invention relates to improvements in rheostats and has for its object to provide a simple and eflicient device of this character which is particularly applicable to binding posts of the ordinary construction, the binding posts being utilized to removably support a resistance element and an adjustable contact member, and to serve as a locking means for retaining the contact member in adjusted position.

Other objects will appear from a consideration of the following description,-taken in connection with the accompanying drawings forming a part of this specification, with the understanding, however, that the embodi ment illustrated, though practical, is by no means the only embodiment which the invention may assume, wherefore the invention is not confined to any strict conformity with the showing of the drawings, but may be changed and modified in various particulars, within the scope of the appended claims.

In the drawings, Figure l is a view showing in front elevation, one form of rheostat embodying my invention. Fig. 2 is a top plan View of the rheostat shown in Fig. 1..

Fig. 3 is a longitudinal sectional view taken on the line IIIIII of Fig. 1, looking in the direction of the arrows.

Similar reference characters refer to similar parts in each of the several views.

Referring. to the drawings in detail, my invention comprises, in this instance, a base B formed of any suitable insulating material, and which has mounted in the opposite ends thereof upstanding binding posts P and P. The binding posts are of the ordinary construction, each comprising a threaded shank 10, nuts 11, and washers 12, the washers being interposed between certain of the nuts to receive the wires to which the device is connected.

Removably mounted upon the binding posts P and P and connecting the same is a plate A formed of insulating material. This plate is retained in spaced relation to the base B and upon the shanks 10 by means of certain of the nuts 11 and washers 12, as will be understood. Between the binding posts P and P, the plate A is formed with two series of perforations 13 and 14 respectively, which are spaced from each other a suitable distance and which extend transversely of the plate, as shown.

to the binding post P by means of a conducting member 15 secured to the underside of the plate and surrounding the shank 10 of such binding post. The opposite end of the resistance element R, is not electrically connected to the binding post P, but may be connected therewith through a contact member C mounted on such post. The contact member C is, in this instance, formed from a single piece of resilient metal bent upon itself at its medial portion to provide spring arms 16. The arms 16 are provided with alined openings to receive the shanks 10 of binding post P, while the free ends-thereof are tapered as at 17 and bent inwardly as at 18 to provide the contact points 19. The medial portion of the contact member provides an operating handle 20, by means of which this member may be turned about the shank, as will be understood. This contact member is so arranged upon the binding post P as to dispose the arms 16 and points 19 upon opposite sides of the plate A, certain of the nuts upon the shank clampingly engaging the arms to force the points into.

engagement with the grids whereby electrical contact is made between the two binding posts. In operation, the contact member is moved, by the operating handle 20, to contact with any portion of the grids, by loosening the nuts on the shank of post P. Thus the contact member is free to swing about the shank to engage any portion of the grids to vary the amount of resistance interposed between the two binding posts.

From the foregoing description taken in conjunction with the accompanying drawings, it will be evident that I provide a simple and efiicient rheostat capable of numerous adjustments and readily applicable to binding posts of the usual construction.

Having described my invention, What 1 claim is:

1. A rheostat comprising a base, binding posts mounted on the base, a member of insulating material and having perforations formed therein, said member connecting said posts, a resistance element connected to one of said posts and trained through said perforations in a manner to form grids upon opposite sides of said plate, and a contact movably mounted on the remaining post and engageable with both of said grids.

2.; A rheostat comprising a base, spaced conducting members upstanding from said base, an element of insulating material. connecting said members and removably mounted thereon, a resistance element connected to one of said members and arranged upon opposite sides of said insulationelement to provide a plurality of contact surfaces, and a contact pivoted to one of the members and movable to simultaneously engage the con tact surfaces upon opposite sides of the plate.

3. A rheostat comprising a base, spaced conducting members upstanding from said base, a perforated element of insulating ma. terial connecting said members and removably mounted thereon, a resistance element formed from a single length of material and connected to one or said members and trained through said perforations to provide grids on opposite sides of said plate, and a contact mounted on the remaining conducting member and movable over said grids.

1-. A rheostat comprising a base, binding posts mounted on the base, resistance elements removably supported by said posts mounted on the remaining post and engagable With any of the elements.

5; A rheostat comprising a base, a pair of spaced binding posts mounted on said base, each of said posts comprising a threaded shank and nuts threadedly mounted on the shank; an insulated member connecting the posts and removably mounted on said shanks, resistance elements mounted on said member and electrically connected to one of the posts, and a contact member pivotedly mounted on the other binding post and movable over said elements, said nuts forming a clamping means for retaining the insulated member upon the shanks and for securing the contact member in adjusted position.

6. A rheostat comprising a member of insulating material having'pertorations therein, a resistance member trained through said perforations in a manner to form grids upon opposite sides of said member of insulating material, means comprising a binding post for electrically connecting one point of said resistance member to apart of an external circuit and means comprising a second binding post for electrically connecting one of a plurality of contacting points in the resistance element to another part of said ex.- ternal circuit.

in testimony whereof I affix my signature in presence of two Witnesses.

HERBERT A. WALLACE.

Witnesses A. HERMAN Wnennn, Emvrn H. Jones. 

